CN110687485A - Wide-range vertical sensitive magnetic sensor with feedback on closed-loop core - Google Patents
Wide-range vertical sensitive magnetic sensor with feedback on closed-loop core Download PDFInfo
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- CN110687485A CN110687485A CN201911039039.3A CN201911039039A CN110687485A CN 110687485 A CN110687485 A CN 110687485A CN 201911039039 A CN201911039039 A CN 201911039039A CN 110687485 A CN110687485 A CN 110687485A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/0011—Arrangements or instruments for measuring magnetic variables comprising means, e.g. flux concentrators, flux guides, for guiding or concentrating the magnetic flux, e.g. to the magnetic sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
Abstract
The invention discloses a wide-range vertical sensitive magnetic sensor fed back on a closed-loop core, which comprises a silicon-based substrate, a flux guider, a magneto-resistor, a signal feedback coil, an operational amplifier and a power amplifier, wherein the on-position signal feedback coil is arranged on a push-pull vertical sensitive magnetic sensor chip, when feedback current is introduced, magnetic field signals with equal magnitude and opposite directions are generated in the sensitive axis direction of the magneto-resistor above the signal feedback coil, and the magnetic field signals counteract the original signal magnetic field respectively to form a closed-loop feedback structure, thereby effectively improving the output linearity of the sensor, improving the measurement precision and reducing the power consumption; the purpose of detecting different measuring ranges of a large magnetic field and a small magnetic field is achieved by utilizing different distances between the magnetoresistors and the flux guider and further enabling the magnetoresistors to receive different horizontal magnetic field components.
Description
Technical Field
The invention belongs to the technical field of magnetic sensors, and relates to a wide-range vertical sensitive magnetic sensor with feedback on a closed-loop core.
Background
With the rapid development of the field of magnetic sensors, the application of the magnetic sensors is more and more extensive, the current vertical magnetic sensors are widely applied to the field of consumer electronics such as mobile phones and the like and electronic compass mobile devices, and the products require smaller packaging size and higher measurement stability.
Most of the existing vertical sensitive magnetic sensors are designed in a Z-axis packaging mode, and the Z-axis packaging is a method for packaging a sensitive axis of a sensing chip in a vertical and horizontal plane, for example, patent CN 102426344 a, entitled invention patent of a three-axis magnetic field sensor, which adopts a three-sensor packaging integration method, wherein the Z-axis sensor is placed in a vertical plane to measure a magnetic field in a vertical direction. The sensor manufactured by the method has the advantages of large volume, high packaging cost, complex process, low stability, easy packaging fracture and the like. The name of patent CN103995240B is a magnetoresistive Z-axis gradient sensor chip, which uses a flux guide to direct the Z-axis magnetic field component in the XY plane. The invention primarily utilizes flux directors to direct the Z-axis magnetic field in the XY plane for the measurement of Z-axis gradients. In order to ensure the sensitivity of the sensor composed of the conventional magnetic sensing element, the interval of the magnetic field detection is mostly within plus or minus 10Gs, and the detection capability for a larger magnetic field is insufficient.
Although a single-core integrated vertical sensitive magnetic sensor exists, an open-loop design is adopted at present, for example, the name of application No. 201820341886.X is a push-pull vertical sensitive magnetic sensor, which converts a Z-axis magnetic field in a vertical direction into a leakage magnetic field component in a plane by using a flux guide to realize magnetic field detection in the vertical direction, but in the design, a magnetoresistor is easy to be magnetically saturated under the condition of measuring a large magnetic field, hysteresis is large during measurement, the measurement bandwidth, the measurement precision and the linearity of the sensor are influenced to a great extent, and the open-loop design has poor linearity and low measurement precision, and is difficult to meet the requirements of modern industries.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a wide-range vertical sensitive magnetic sensor with feedback on a closed-loop core.
The invention comprises a silicon-based substrate, a flux guider, four same magneto-resistors, a signal feedback coil, an operational amplifier and a power amplifier;
the flux guider is of a long strip structure, four magnetoresistors are arranged on the same silicon-based substrate, two shielded magnetoresistors used for reference are arranged right below the flux guider, the left side and the right side of the flux guider are respectively provided with one magnetoresistor, the two magnetoresistors are bilaterally symmetrical about the flux guider, the sensitive axes of the two magnetoresistors are positioned on the same horizontal line and have the same direction, and the two magnetoresistors are perpendicular to the left side surface and the right side surface of the flux guider; the flux guider induces a vertical magnetic field signal to the in-plane direction, an in-plane magnetic field component is generated at the magneto-resistors on two sides of the flux guider, and the signal magnetic field components generated in the sensitive axis directions of the two magneto-resistors are equal in magnitude and opposite in direction;
the magneto-resistors which are symmetrical on the left side and the right side of the flux guider form a group of half bridges, two shielded magneto-resistors which are used for reference and arranged right below the flux guider form another group of half bridges, and the four magneto-resistors jointly form a push-pull output Wheatstone bridge structure; the signal feedback coil is in a U-shaped structure with two parallel sides, the signal feedback coil is arranged on a silicon-based substrate below the magnetoresistor, the two parallel sides of the signal feedback coil are respectively arranged right below the magnetoresistor on the left side and the right side of the flux guide, and the signal feedback coil generates magnetic field signals with equal size and opposite directions on the sensitive axis direction of the magnetoresistor on the two sides of the flux guide when the feedback current is supplied;
a detection resistor is arranged between the output end of the signal feedback coil and the grounding end; the output end of the Wheatstone bridge is connected with the input end of the operational amplifier, the output end of the operational amplifier is connected with the input end of the power amplifier, and the output end of the power amplifier is connected with the signal feedback coil to form a closed loop feedback structure.
The invention also comprises a silicon substrate, a flux guider, six same magneto-resistors, two signal feedback coils, an operational amplifier and a power amplifier; the method is characterized in that: the flux guider is of a long strip structure and is arranged on the same silicon substrate together with six magnetoresistors, two shielded magnetoresistors used for reference are arranged under the flux guider, the left side and the right side of the flux guider are respectively provided with two magnetoresistors, the two magnetoresistors close to the left side and the right side of the flux guider form a pair, the two magnetoresistors far away from the left side and the right side of the flux guider form a pair, each pair of magnetoresistors are bilaterally symmetrical relative to the flux guider, the directions of the sensitive axes of the six magnetoresistors are the same, and the flux guider and the six magnetoresistors are arranged at positions for detecting a magnetic field signal of a vertical plane; the two signal feedback coils are of U-shaped structures, the feedback coil of one U-shaped structure is arranged on the silicon-based substrate below the pair of magnetoresistors close to the left side edge and the right side edge of the flux guider, the feedback coil of the other U-shaped structure is arranged on the silicon-based substrate below the pair of magnetoresistors far away from the left side edge and the right side edge of the flux guider, and the two edges of the U-shaped structure are parallel to each other and are respectively arranged right below the two pairs of magnetoresistors on the two sides of the flux guider; a pair of magneto-resistors close to the flux guider and two shielded magneto-resistors used for reference arranged right below the flux guider form a Wheatstone bridge structure for push-pull output, and the Wheatstone bridge structure is used for detecting a magnetic field signal of a small-range vertical plane; a pair of magnetoresistors far away from the flux guider and two shielded magnetoresistors used for reference arranged right below the flux guider form another Wheatstone bridge structure for push-pull output, and the magnetoresistors are used for detecting magnetic field signals of a large-range vertical plane; the two pairs of Wheatstone bridge structures are designed to meet the requirements of the sensor chip on the detection of different measuring ranges of the magnetic field signals of the vertical plane;
the flux guider induces a vertical magnetic field signal to the in-plane direction and respectively generates magnetic leakage components in the directions of two pairs of magneto-resistor sensitive axes at the left side and the right side of the flux guider, after the vertical magnetic field signal is induced by the flux guider, the vertical magnetic field signal respectively generates magnetic leakage components with equal size and opposite directions in the direction of the first pair of magneto-resistor sensitive axes and generates magnetic leakage components with equal size and opposite directions in the direction of the second pair of magneto-resistor sensitive axes; when feedback current is fed, signal feedback coils below a pair of magnetoresistors close to the left side and the right side of the flux guider generate a magnetic leakage component feedback magnetic field for offsetting the sensitive axis direction of the magnetoresistors in the sensitive axis direction of the two magnetoresistors above the signal feedback coils; the signal feedback coils below a pair of magnetoresistors far away from the left side and the right side of the flux guider generate a magnetic leakage component feedback magnetic field for offsetting the sensitive axis direction of the magnetoresistors in the sensitive axis direction of the two magnetoresistors above the signal feedback coils;
the output ends of the two Wheatstone bridges are connected with the input end of the operational amplifier through switches, and the switches are used for selecting one of the two Wheatstone bridges as a detection bridge and indirectly have the function of selecting a measuring range; the operational amplifier amplifies the signal amplitude and outputs the amplified signal, the output end of the operational amplifier is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the signal feedback coil, the other end of the feedback coil is connected in series with the resistor to be tested, and the other end of the resistor to be tested is grounded.
Preferably, the flux guide is made of a nickel-based, cobalt-based or iron-based soft magnetic material.
Preferably, the magneto-resistor is giant magneto-resistance or tunnel junction magneto-resistance.
Preferably, the signal feedback coil is made of non-magnetic, low-resistance and good-conductivity metal silver, copper, aluminum, gold titanium or alloy thereof.
According to the invention, the in-place signal feedback coil is arranged on the push-pull type vertical sensitive magnetic sensor chip, when feedback current is conducted, magnetic field signals with equal magnitude and opposite directions are generated in the directions of two pairs of magneto-resistor sensitive axes above the signal feedback coil, and the original signal magnetic fields are respectively offset, so that a closed loop type feedback structure is formed, the output linearity of the sensor is effectively improved, the measurement precision is improved, and the power consumption is reduced; the distance between the two groups of magnetoresistors and the flux guider can be different, so that the horizontal magnetic field components received by the two groups of magnetoresistors are different, and two pairs of push-pull bridges formed by the six same magnetoresistors realize the purpose of respectively detecting different ranges of a large magnetic field and a small magnetic field.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of the present invention;
FIG. 2 is a block diagram of an overall system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of the vertical magnetic field induced by the flux guide under the action of the external magnetic field according to one embodiment of the present invention;
FIG. 4 is a schematic diagram of a push-pull Wheatstone bridge according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a feedback magnetic field counteracting an original magnetic field under the action of a signal feedback coil according to a first embodiment of the present invention;
FIG. 6 is a diagram illustrating a Wheatstone bridge state under the action of a signal feedback coil according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram according to a second embodiment of the present invention;
FIG. 8 is a diagram of a general system according to a second embodiment of the present invention;
FIG. 9 is a schematic diagram of the vertical magnetic field induced by the flux guide under the action of the external magnetic field in the second embodiment of the present invention;
FIG. 10 is a schematic diagram of a push-pull Wheatstone bridge according to a second embodiment of the invention;
FIG. 11 is a schematic diagram of the feedback magnetic field counteracting the original magnetic field under the action of the signal feedback coil according to the second embodiment of the present invention;
fig. 12 is a schematic diagram of a wheatstone bridge state under the action of the signal feedback coil in the second embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows:
as shown in fig. 1, a wide-range vertical sensitive magnetic sensor with feedback on a closed-loop core comprises a silicon-based substrate 1, a flux director 2, four identical magnetoresistors 3, and a signal feedback coil 4, an operational amplifier and a power amplifier.
The flux guider 2 is of a long strip structure, four magnetoresistors 3 are arranged on the same silicon-based substrate 1, two shielded magnetoresistors used for reference are arranged right below the flux guider 2, the left side and the right side of the flux guider 2 are respectively provided with one magnetoresistor, the two magnetoresistors are bilaterally symmetrical about the flux guider 2, the sensitive axis directions of the two magnetoresistors 3 are positioned on the same horizontal line, the directions are consistent, and the two magnetoresistors are perpendicular to the left side and the right side of the flux guider 2.
As shown in fig. 3, the flux director 2 induces a vertical magnetic field signal into an in-plane direction, generates an in-plane magnetic field component at the magnetoresistors on both sides thereof, and generates signal magnetic field components in the directions of the sensitive axes of the two magnetoresistors in equal magnitude and opposite directions.
As shown in fig. 4, the magnetoresistors symmetrically arranged on the left and right sides of the flux guide 2 form a set of half-bridges, the two shielded magnetoresistors 3 used for reference and arranged right below the flux guide 2 form another set of half-bridges, and the four magnetoresistors 3 form a push-pull output wheatstone bridge structure.
As shown in fig. 5, the signal feedback coil 4 is a U-shaped structure, two sides of the U-shaped structure are parallel to each other, the U-shaped structure is disposed on the silicon substrate 1 below the magnetoresistors, two parallel sides of the signal feedback coil 4 of the U-shaped structure are respectively disposed right below the magnetoresistors on the left and right sides of the flux guide 2, and the signal feedback coil 4 when the feedback current is applied generates magnetic field signals with equal magnitude and opposite directions at the sensitive axis direction of the magnetoresistors on the two sides of the flux guide.
As shown in fig. 2, a detection resistor is disposed between the output end of the signal feedback coil 4 and the ground end; the output end of the Wheatstone bridge is connected with the input end of the operational amplifier, the output end of the operational amplifier is connected with the input end of the power amplifier, and the output end of the power amplifier is connected with the signal feedback coil 4 to form a closed loop feedback structure.
In this embodiment the flux guide 2 is made of a nickel, cobalt or iron based soft magnetic material. The soft magnetic material has strong magnetic permeability, especially the soft magnetic alloy is used as the material such as ferronickel or cobalt iron. The magneto-resistor 3 is selected from giant magneto-resistance resistor or tunnel junction magneto-resistance resistor. The giant magnetoresistance or tunnel junction magnetoresistance has bipolar property, and is convenient for forming and measuring a push-pull electric bridge. The signal feedback coil 4 is made of non-magnetic, low-resistance and good-conductivity metal silver, copper, aluminum or gold. Avoid high resistance metal to generate heat and cause the sensor to damage.
The operational amplifier selected in the embodiment is an AD623 model of ADI, and the operational amplifier is used for amplifying the output voltage value of the sensor, and the voltage generated by the sensor chip is in a millivolt level, so that the subsequent processing is not convenient. The maximum amplification factor of the operational amplifier can be 1000 times, and the proper amplification factor is adjusted to facilitate signal analysis, processing and measurement.
In the embodiment, the power amplifier can be an LM3886 power amplifier of a national semiconductor, the power amplifier is used for amplifying power as the name implies, and most importantly, current is amplified.
In the embodiment, on one hand, the flux guide 2 can generate a leakage magnetic field component in a horizontal plane under the action of a Z-axis magnetic field in the vertical direction, and can shield and reduce the interference of the magnetic field component in the horizontal direction; the magnetic leakage generates magnetic field components in different directions at the left and right pairs of magneto-resistors 3, and the magneto-resistance values of the two pairs of magneto-resistors 3 are changed in different sizes to enable the Wheatstone bridge to form push-pull output; the differential voltage output by the Wheatstone bridge is converted into a current signal through the operational amplification module and the power amplification module and acts on the signal feedback coil 4, a loop-shaped induced magnetic field is generated after feedback current is conducted on two parallel sides of the signal feedback coil 4, a magnetic field component of a horizontal tangent line at the top of the loop-shaped induced magnetic field acts on the flux guider 2 to generate a magnetic leakage magnetic field component in a horizontal plane, and then the measured magnetic field is counteracted until the magnetic field intensity received by the magneto-resistor 3 in the sensitive axis direction approaches to zero, at the moment, the Wheatstone bridge is in a balanced state, and then the voltage at two ends of a resistor Rm to be measured connected in series on the feedback coil is measured, so that the magnitude of; the feedback current and the measured magnetic field are in a certain proportional relation, and the magnitude of the measured magnetic field is further obtained through the measured magnitude of the feedback current.
As shown in FIG. 6, in the push-pull bridge composed of R1, R2, R3 and R4, when the sensor is subjected to a magnetic field perpendicular to the silicon-based substrate 1, the flux director 2 decomposes the magnetic field into R1 and R2 horizontal sensitive axes, R3 and R4 have constant resistance values due to shielding, the resistance values of the R1 and R2 resistors of the formed push-pull structure are increased and decreased one by one, and are the same as the decreased resistance values, and the resistance value change of the magneto-sensitive resistor 3 is Δ R under the influence of the magnetic field to be measured, and the output of the bridge is Δ R at this moment
Due to the existence of the signal feedback coil 4, when the sensor outputs an electric signal, a feedback current is generated on the signal feedback coil 4, the feedback current generates a feedback magnetic field, and the feedback magnetic field counteracts on the magneto-resistor 3 to offset the original magnetic field, so that the resultant magnetic field borne by the magneto-resistor 3 is close to zero, and a balance state is achieved.
A feedback system formed by zero magnetic flux measurement can track to 0.2 microseconds, namely the frequency can reach 5 MHZ; the feedback system effectively reduces external interference and improves linearity, namely, measurement accuracy is greatly improved.
Example two:
as shown in fig. 7, the present embodiment is different from the embodiment in that: two pairs of magnetoresistors are arranged on the left side and the right side of the flux guider 2, and the two pairs of magnetoresistors are mutually symmetrical about the left side and the right side of the flux guider; the six magnetoresistors are all of the same specification and are arranged in parallel side by side.
As shown in fig. 8 and 10, a pair of magnetoresistors close to the left and right sides of the flux guide 2 and two shielded magnetoresistors for reference arranged right below the flux guide 2 form a wheatstone bridge structure for push-pull output, the bridge has large magnetic field component and high sensitivity, and can be used for detecting magnetic field signals of a small-range vertical plane, another pair of magnetoresistors far away from the left and right sides of the flux guide 2 and two shielded magnetoresistors for reference 3 arranged right below the flux guide 2 form another wheatstone bridge structure for push-pull output, the bridge has small magnetic field component and low sensitivity, and can be used for detecting magnetic field signals of a large-range vertical plane, and the two pairs of wheatstone bridges are designed to meet the detection requirements of the sensor chip on different ranges of magnetic field signals of the vertical plane.
Wherein R1, R2, R3 and R4 form a group of Wheatstone bridges, wherein R1 and R2 are connected to form a group of half bridges, and R3 and R4 are connected to form another group of half bridges. The power supply voltage is provided between R1 and R3, and the connection between R2 and R4 is grounded. The connection part of the R1 and the R2 and the connection part of the R3 and the R4 lead out the output end of the sensor;
r5, R6, R3 and R4 form a group of Wheatstone bridges, wherein R5 and R6 are connected to form a group of half bridges, and R3 and R4 are connected to form another group of half bridges. The power supply voltage is provided between R5 and R3, and the connection between R6 and R4 is grounded. The connection of R5 and R6 and the connection of R3 and R4 lead out the output end of the sensor.
The output ends of the two Wheatstone bridges are connected to the input end of the operational amplifier through a switch, the switch is used for selecting one of the two Wheatstone bridges as a detection bridge and indirectly selecting a measurement range, the operational amplifier outputs the amplified signal amplitude, the output end of the operational amplifier is connected to the input end of the power amplifier, the output end of the power amplifier is connected to a signal feedback coil, the other end of the feedback coil is connected in series with a resistor Rm to be measured, and the other end of the resistor Rm to be measured is grounded.
As shown in fig. 11, another signal feedback coil 4 is disposed below a pair of magnetoresistors 3 far from the left and right sides of the flux guide 2, and the energized signal feedback coils 4 generate magnetic field signals with equal magnitude and opposite directions in the sensitive axis directions of the two magnetoresistors.
As shown in fig. 9, the flux guide 2 generates a leakage magnetic field component in the horizontal plane by the Z-axis magnetic field in the vertical direction, and the leakage magnetic field component acts on the magnetoresistors distributed on the left and right sides of the flux guide 2. Similarly, assuming a uniform magnetic field H vertically upward, positive and negative magnetic charges are uniformly distributed on the upper and lower surfaces of the flux guide 2 under the action of the uniform magnetic field H, the magnetoresistor 3 closer to the flux guide 2 receives a stronger magnetic field component, and the magnetoresistor farther from the flux guide 2 receives a weaker magnetic field component.
The magnetoresistors under the flux guide 2 are covered and shielded by the flux guide 2 made of soft magnetic materials and are not influenced by an external magnetic field, and the two magnetoresistors which are shielded at the moment are used as reference resistors and form a bridge structure with the magnetoresistors on the left side and the right side of the flux guide 2 respectively. Namely, R1, R2, R3 and R4 form one group of push-pull bridges, and R3, R4, R5 and R6 form another group of push-pull bridges.
When the measured vertical magnetic field is small, the flux guide 2 converts the vertical magnetic field into a horizontal magnetic field by using magnetoresistors R1 and R2 close to two sides of the flux guide 2, and simultaneously, the formed R1, R2, R3 and R4 push-pull bridges also form a push-pull structure. The bridge output sensitivity at this time is:
it can be seen that the sensitivity of the sensor in this embodiment is one-half of the sensitivity of the sensor in the four-arm push-pull bridge. However, the sensor chip made by the method has smaller volume and better meets the requirement of modern sensors on miniaturization.
If the measured magnetic field is large, a Wheatstone bridge configuration is formed by the magnetoresistors R5 and R6 and the shielded resistors R3 and R4 away from the sides of the flux guide 2. At this time, since R5 and R6 are far from the flux guide 2, the horizontal magnetic field strength of the flux guide 2 at this position is small, and thus the horizontal magnetic flux leakage at this position is far smaller than the magnetic flux leakage at R1 and R2, and is suitable for detection of a large magnetic field.
As shown in FIG. 12, in the push-pull bridge composed of R5, R6, R3 and R4, when the sensor is subjected to a magnetic field perpendicular to the silicon-based substrate 1, the flux director 2 decomposes the magnetic field into R5 and R6 horizontal sensitive axis directions, R3 and R4 have constant resistance values due to shielding, the resistance values of the R5 and R6 resistors are increased and decreased one by one due to the formed push-pull structure, and the resistance values are increased and decreasedThe resistance values of the resistors are the same, and the resistance value variation of the magnetic sensitive resistor 3 is delta R under the influence of the magnetic field to be measured1The output of the bridge isDue to the existence of the signal feedback coil 4, when the sensor outputs an electric signal, a feedback current is generated on the signal feedback coil 4, the feedback current generates a feedback magnetic field, and the feedback magnetic field counteracts on the magneto-resistor 3 to offset the original magnetic field, so that the resultant magnetic field borne by the magneto-resistor 3 is close to zero, and a balance state is achieved.
It is worth mentioning that: the directions of the oblique filled arrows in fig. 4, 6, 10 and 12 indicate the directions of the original magnetic fields applied to the magnetoresistors 3; the mesh-line filled arrows point in directions that represent the direction of the feedback magnetic field generated by the signal feedback coil 4.
Compared with a traditional external circuit system feedback structure, the on-site feedback structure on the core greatly reduces the required feedback current, greatly reduces the coil impedance, and further greatly reduces the power consumption of the sensor system.
The invention has the advantages that through the in-place signal feedback coil on the push-pull type vertical sensitive magnetic sensor chip setting core, when the feedback current is conducted, magnetic field signals with equal magnitude and opposite directions are generated in the sensitive axis directions of the two pairs of magneto-resistors 3 above the signal feedback coil 4, and the original signal magnetic fields are respectively counteracted to form a closed loop type feedback structure, thereby effectively improving the output linearity of the sensor, improving the measurement precision and reducing the power consumption; the two groups of magnetoresistors are different from the flux guider 2 in distance, so that the two groups of magnetoresistors 3 receive different horizontal magnetic field components, and two pairs of push-pull bridges formed by the six same magnetoresistors 3 achieve the purpose of respectively detecting different ranges of a large magnetic field and a small magnetic field.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (8)
1. A wide-range vertical sensitive magnetic sensor fed back on a closed-loop core comprises a silicon-based substrate, a flux guider, four same magneto-resistors, a signal feedback coil, an operational amplifier and a power amplifier;
the method is characterized in that: the flux guider is of a long strip structure, four magnetoresistors are arranged on the same silicon-based substrate, two shielded magnetoresistors used for reference are arranged right below the flux guider, the left side and the right side of the flux guider are respectively provided with one magnetoresistor, the two magnetoresistors are bilaterally symmetrical about the flux guider, the sensitive axes of the two magnetoresistors are positioned on the same horizontal line and have the same direction, and the two magnetoresistors are perpendicular to the left side surface and the right side surface of the flux guider; the flux guider induces a vertical magnetic field signal to the in-plane direction, an in-plane magnetic field component is generated at the magneto-resistors on two sides of the flux guider, and the signal magnetic field components generated in the sensitive axis directions of the two magneto-resistors are equal in magnitude and opposite in direction;
the magneto-resistors which are symmetrical on the left side and the right side of the flux guider form a group of half bridges, two shielded magneto-resistors which are used for reference and arranged right below the flux guider form another group of half bridges, and the four magneto-resistors jointly form a push-pull output Wheatstone bridge structure; the signal feedback coil is in a U-shaped structure with two parallel sides, the signal feedback coil is arranged on a silicon-based substrate below the magnetoresistor, the two parallel sides of the signal feedback coil are respectively arranged right below the magnetoresistor on the left side and the right side of the flux guide, and the signal feedback coil generates magnetic field signals with equal size and opposite directions on the sensitive axis direction of the magnetoresistor on the two sides of the flux guide when the feedback current is supplied;
a detection resistor is arranged between the output end of the signal feedback coil and the grounding end; the output end of the Wheatstone bridge is connected with the input end of the operational amplifier, the output end of the operational amplifier is connected with the input end of the power amplifier, and the output end of the power amplifier is connected with the signal feedback coil to form a closed loop feedback structure.
2. The wide range, vertically sensitive, magnetic sensor with feedback on a closed-loop core of claim 1, wherein: the flux guider is made of nickel series, cobalt series or iron series soft magnetic materials.
3. The wide range, vertically sensitive, magnetic sensor with feedback on a closed-loop core of claim 1, wherein: the magneto-resistor is giant magneto-resistance resistor or tunnel junction magneto-resistance resistor.
4. The wide range, vertically sensitive, magnetic sensor with feedback on a closed-loop core of claim 1, wherein: the signal feedback coil is made of non-magnetic, low-resistance and good-conductivity metal silver, copper, aluminum, gold and titanium or alloy thereof.
5. A wide-range vertical sensitive magnetic sensor fed back on a closed-loop core comprises a silicon-based substrate, a flux guider, six same magneto-resistors, two signal feedback coils, an operational amplifier and a power amplifier; the method is characterized in that: the flux guider is of a long strip structure and is arranged on the same silicon substrate together with six magnetoresistors, two shielded magnetoresistors used for reference are arranged under the flux guider, the left side and the right side of the flux guider are respectively provided with two magnetoresistors, the two magnetoresistors close to the left side and the right side of the flux guider form a pair, the two magnetoresistors far away from the left side and the right side of the flux guider form a pair, each pair of magnetoresistors are bilaterally symmetrical relative to the flux guider, the directions of the sensitive axes of the six magnetoresistors are the same, and the flux guider and the six magnetoresistors are arranged at positions for detecting a magnetic field signal of a vertical plane; the two signal feedback coils are of U-shaped structures, the feedback coil of one U-shaped structure is arranged on the silicon-based substrate below the pair of magnetoresistors close to the left side edge and the right side edge of the flux guider, the feedback coil of the other U-shaped structure is arranged on the silicon-based substrate below the pair of magnetoresistors far away from the left side edge and the right side edge of the flux guider, and the two edges of the U-shaped structure are parallel to each other and are respectively arranged right below the two pairs of magnetoresistors on the two sides of the flux guider; a pair of magneto-resistors close to the flux guider and two shielded magneto-resistors used for reference arranged right below the flux guider form a Wheatstone bridge structure for push-pull output, and the Wheatstone bridge structure is used for detecting a magnetic field signal of a small-range vertical plane; a pair of magnetoresistors far away from the flux guider and two shielded magnetoresistors used for reference arranged right below the flux guider form another Wheatstone bridge structure for push-pull output, and the magnetoresistors are used for detecting magnetic field signals of a large-range vertical plane; the two pairs of Wheatstone bridge structures are designed to meet the requirements of the sensor chip on the detection of different measuring ranges of the magnetic field signals of the vertical plane;
the flux guider induces a vertical magnetic field signal to the in-plane direction and respectively generates magnetic leakage components in the directions of two pairs of magneto-resistor sensitive axes at the left side and the right side of the flux guider, after the vertical magnetic field signal is induced by the flux guider, the vertical magnetic field signal respectively generates magnetic leakage components with equal size and opposite directions in the direction of the first pair of magneto-resistor sensitive axes and generates magnetic leakage components with equal size and opposite directions in the direction of the second pair of magneto-resistor sensitive axes; when feedback current is fed, signal feedback coils below a pair of magnetoresistors close to the left side and the right side of the flux guider generate a magnetic leakage component feedback magnetic field for offsetting the sensitive axis direction of the magnetoresistors in the sensitive axis direction of the two magnetoresistors above the signal feedback coils; the signal feedback coils below a pair of magnetoresistors far away from the left side and the right side of the flux guider generate a magnetic leakage component feedback magnetic field for offsetting the sensitive axis direction of the magnetoresistors in the sensitive axis direction of the two magnetoresistors above the signal feedback coils;
the output ends of the two Wheatstone bridges are connected with the input end of the operational amplifier through switches, and the switches are used for selecting one of the two Wheatstone bridges as a detection bridge and indirectly have the function of selecting a measuring range; the operational amplifier amplifies the signal amplitude and outputs the amplified signal, the output end of the operational amplifier is connected to the input end of the power amplifier, the output end of the power amplifier is connected to the signal feedback coil, the other end of the feedback coil is connected in series with the resistor to be tested, and the other end of the resistor to be tested is grounded.
6. The wide range vertical sensitive magnetic sensor with feedback on closed-loop core of claim 5, wherein: the flux guider is made of nickel series, cobalt series or iron series soft magnetic materials.
7. The wide range vertical sensitive magnetic sensor with feedback on closed-loop core of claim 5, wherein: the magneto-resistor is giant magneto-resistance resistor or tunnel junction magneto-resistance resistor.
8. The wide range vertical sensitive magnetic sensor with feedback on closed-loop core of claim 5, wherein: the signal feedback coil is made of non-magnetic, low-resistance and good-conductivity metal silver, copper, aluminum, gold and titanium or alloy thereof.
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| CN117405958B (en) * | 2023-12-14 | 2024-02-13 | 江苏多维科技有限公司 | current sensor |
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